Resumen: El funcionamiento normal de laboratorios de conservación de germoplasma vegetal involucra la realización de actividades numerosas y diversas, las cuales fueron afectadas por la pandemia causada por coronavirus de 2019 (COVID-19). El objetivo de esta comunicación es realizar una reseña de la evolución del banco de germoplasmain vitrode mandioca presente en la FCA-UNNE e IBONE (CONICET-UNNE) y dar a conocer las prácticas de manejo habituales y los procedimientos realizados para preservar con vida el material vegetal protegiendo la salud del personal involucrado antes y durante la pandemia por COVID-19. Docentes, investigadores, alumnos de grado y posgrado llevaron adelante, durante casi 40 años, la conservaciónin vitrode 56 cultivares de mandioca provenientes de diferentes países. Previamente a marzo del año 2020, el manejo del banco estaba centrado principalmente en la ejecución de actividades científico-tecnológicas para la conservación del material y la búsqueda de parámetros para establecer un orden de subcultivos. Decretado el Aislamiento Social, Preventivo y Obligatorio en Argentina, se continuó con las actividades de conservación aplicando las prácticas usuales y siguiendo las medidas sanitarias de orden político-institucionales implementadas. Para afrontar los nuevos escenarios sanitarios, se deberán ajustar metodologías que sean eficaces para mantener la viabilidad del material vegetal y prolongar el tiempo de conservación.

Summary: The normal management of plant germplasm conservation laboratories involves carrying out numerous and diverse activities, which were affected by the coronavirus pandemic (COVID-19). The objective of this publication was to review the evolution of the cassavain vitrogermplasm bank at the FCA-UNNE and IBONE (CONICET-UNNE) and to tell about usual management practices and the procedures to preserve living plant material and the personnel’s life involved in pre-pandemic and COVID-19 pandemic times. Teachers, researchers, undergraduate and graduate students carried out, for almost 40 years, thein vitroconservation of 56 cassava cultivars from different countries. Before March 2020, the bank management consisted mainly in scientific-technological activities for the conservation of the material and the search for parameters to establish an order of subcultures. Having decreed Social, Preventive and Compulsory Isolation in Argentina, conservation activities continued applying the usual practices by following political-institutional sanitary measures. To face the new sanitary scenarios, methodologies must be adjusted so that they are effective at maintaining viability of the plant material and at prolonging conservation time.

Resumo Rubiaceae é uma das cinco famílias mais ricas em espécies de Angiospermas, suas flores são caracterizadas por um disco nectarífero ao redor do estilete. No entanto, quase não há estudos sobre a anatomia destas estruturas na família. O objetivo deste trabalho foi descrever pela primeira vez a anatomia dos nectários na tribo Gardenieae (Rubiaceae). Flores de Cordiera concolor, Genipa americana, Randia calycina, Randia ferox, Randia heteromera, Randia micracantha e Tocoyena formosa foram coletadas, fotografadas e fixadas. Os nectários foram processados utilizando técnicas convencionais de observação em microscopia óptica e microscopia eletrônica de varredura. Em todas as flores o nectário é histologicamente diferenciado em epiderme, parênquima nectarífero, parênquima subnectarífero e traços vasculares. O néctar é exsudado através de estômatos. Os nectários tem função reprodutiva e são estruturados e mesenquimais na fase floral. Após a queda da corola são nectários persistentes com secreção pós-floral e função extranupcial. Também foram registados os visitantes florais que apareceram em flores abertas e após a queda da corola.

Abstract Rubiaceae is one of the five most species-rich families of Angiosperm, its flowers are characterized by a nectariferous disc surrounding the base of the style; however, there are almost no studies on anatomy of these structures in the family. The aim of this study was to describe for the first time the anatomy of the floral nectaries in the tribe Gardenieae (Rubiaceae). Flowers from Cordiera concolor, Genipa americana, Randia calycina, Randia ferox, Randia heteromera, Randia micracantha, and Tocoyena formosawere collected, photographed, and processed using conventional techniques for observation with optical and scanning electron microscopies. In all species the nectary is differentiated histologically into epidermis, nectary and sub-nectary parenchyma, and vascular bundles. Nectar is exuded via nectarostomata. The nectaries have reproductive function, and are structural and mesenchymal during the floral stage. Whereas after corolla has fallen they are persistent nectaries, with post-floral secretion and extranuptial function. In addition, floral visitors that appeared on open flowers and after corolla fall were recorded.

Abstract Fridericia caudigera and Cuspidaria convoluta (Bignoniaceae) species, which grow in the northwest of Argentina, have shown antibacterial effect against strains isolated from skin infections, and each one displayed synergism with commercial antibiotics. The aims of this work were to evaluate the antibacterial activity and toxicity of the combination of these two plant species, and to design a stable gel for topical use including the blend of extracts. The combination of extracts was evaluated for synergistic effects (chequerboard assay), genotoxicity (Ames test) and cytotoxicity (Artemia salina test). A gel was subsequently formulated with the combination of extracts using carboxymethylcellulose as a polymer. The following physico- chemical characteristics of the gel formulation: pH, viscosity, spreadability and total phenol content, as well as resistance to severe temperature changes, biological activity (diffusion in agar), in vitro permeation (Franz cells) and primary dermal irritation (Draize test) were analyzed. The combination of extracts showed a synergistic effect on pathogenic bacteria and was not toxic in the in vitro tests. The gel was stable and retained the antimicrobial activity of the original extracts. The formulation proposed in this work could constitute an alternative for primary skin infections since it proved to be safe for topical administration.

Resumo Cephalanthus glabratus é uma espécie imperfeitamente conhecida da família Rubiaceae. Esta é uma planta medicinal muito utilizada pelos habitantes locais em sua área de distribuição, porém até agora tem recebido escassa atenção da comunidade científica, o qual é evidenciado na escassa literatura que trata do táxon. A espécie é um arbusto muito ramificado, com folhas verticiladas, inflorescências em glomérulos, fruto esquizocárpico, uma semente por mericarpo, e sementes com um estrofiolo proeminente e esponjoso. A espécie cresce somente em vegetação de áreas baixas alagáveis e está sempre relacionada às bacias dos principais rios da região, Paraguai, Paraná, Uruguai e Rio da Prata, e, portanto, é fortemente ameaçada pelas atividades humanas ao longo delas (hidrelétricas, desmatamento, avanços das áreas urbanas, redução das zonas úmidas etc.). Seguindo as diretrizes da IUCN e baseado em todos os dados disponíveis de distribuição, classificamos como NT (Near Threatened, quase ameaçada). Apesar de que gênero foi taxonomicamente revisado, a nomenclatura do tipo de Cephalanthus glabratus não foi por enquanto corretamente estudada, portanto, é revisada aqui. Uma descrição detalhada, dados ecológicos e de distribuição são adicionalmente fornecidos.

Abstract Cephalanthus glabratus is an imperfectly known species of the family Rubiaceae. It is a medicinal plant widely used by the locals in its area of distribution, however until now it has received little attention from the scientific community, which is evidenced in the few articles treating the species. The species is a much-branched shrub, with whorled leaves, glomeriform inflorescences, schizocarpic fruits with 1-seeded mericarps, and seeds with a large spongy strophiole. It grows only in the vegetation of the lowlands and is always related to the basins of the main rivers of the region, Paraguay, Paraná, Uruguay and Río de la Plata, and therefore is strongly threatened by the human activities along them (hydroelectric dams, deforestation, advances of urban areas, reduction of the wetlands, etc.). Following IUCN guidelines and all available distributional data, we rated it NT (Near Threatened). Despite the fact that the genus was taxonomically revised, the nomenclatural type of Cephalanthus glabratus was not correctly clarified, so we have done so here. A detailed description, ecological and distributional data are provided.

It has been reported that calcium (Ca) has a moderating effect on the effects of salinity, and which maintains the integrity of cellular membranes and reduce the loss of potassium (K). Lisianthus is an ornamental plant whose habitat suggests that it can adapt to extreme conditions. This study set out to assess whether the Ca (9 and 13 meq L-1) influences lisianthus tolerance to increased electrical conductivity (EC) (2.5, 4, 6 and 8 dS m-1) in the nutrient solution. The dry weight was reduced when EC 4 dS m-1 regardless of the level of Ca was raised; however, the biomass was recovered when the EC increased to 6 and 8 dS m-1 plants with 13 meq Ca L-1 of plants with extra Ca maintained a greater concentration of photosynthetic pigments when the EC was 6 and 8 dS m-1. Regardless of the concentration of Ca, the net photosynthesis affected EC to decrease when the EC increased to 4 dS m-1. The relative water content (RWC) in young leaves of plants supplemented with additional levels of Ca increased when treated with solutions with EC greater than 4 dS m-1, which was associated with a higher water potential. The concentration of nitrogen, K, Ca and magnesium was affected by the EC but this is recovered with additional Ca. The results indicate that lisianthus high salinity tolerant only if additional quantities are added Ca.

Se ha reportado que el calcio (Ca) tiene un efecto moderador de los efectos de la salinidad ya que mantiene la integridad de las membranas celulares y reduce la pérdida de potasio (K). Lisianthus es una planta ornamental cuyo hábitat sugiere que puede adaptarse a condiciones extremas. El presente estudio se estableció para evaluar si el Ca (9 y 13 meq L-1) influye en la tolerancia de lisianthus a una mayor conductividad eléctrica (CE) (2.5, 4, 6 y 8 dS m-1) en la solución nutritiva. El peso seco se redujo cuando se elevó la CE a 4 dS m-1 independientemente del nivel de Ca; sin embargo, la biomasa mostró una recuperación cuando la CE aumentó hasta 6 y 8 dS m-1 en plantas con 13 meq L-1 de Ca. Las plantas con Ca suplementario mantuvieron una mayor concentración de los pigmentos fotosintéticos cuando la CE fue de 6 y 8 dS m-1. Independientemente de la concentración de Ca, la CE afectó la fotosíntesis neta al disminuir cuando la CE aumentó a 4 dS m-1. El contenido relativo de agua (CRA) en hojas jóvenes de plantas suplementadas con niveles adicionales de Ca aumentó cuando se trataron con soluciones con CE mayor de 4 dS m-1, lo que estuvo asociado con un mayor potencial hídrico. La concentración de nitrógeno, K, Ca y magnesio fue afectada por la CE aunque esta se recupera con Ca adicional. Los resultados indican que lisianthus tolera niveles altos de salinidad solo si se adicionan cantidades suplementarias de Ca.